Method for treating hays, grains &amp; silages

ABSTRACT

A method of treating organic farm materials such as hays, grains, and silages confines same to a predetermined enclosure. A solid chemical mixture is introduced into the enclosure. The solid chemical mixture is a urea reactor product including ammonium carbamate, ammonia, urea, and water. Heat is applied to the mixture to thereby release sufficient gaseous ammonia to the organic farm material to prevent spoilage, reduce toxin levels, and improve fermentation of the organic farm material. The solid chemical mixture disposed amidst the organic farm material can be provided in a corrosion resistant drum having holes through the top thereof and having an electric resistance heater disposed in the bottom thereof or underneath same. A thermostatic control can control the temperature generated by the heater. The drum with the solid mixture is disposed in the midst of bales of organic farm material which has been covered by plastic sheeting weighted at the edges with mounded dirt to render the enclosure substantially gas-tight.

BACKGROUND OF INVENTION

This invention relates to a method for treating hays, grains, andsilages, and more particularly an improved method for preventingmicrobial growth and spoilage of feedgrains and hays, for detoxifyingaflatoxins in grains, and for increasing the lactic acid content insilages to improve their fermentation.

As of this writing, the United States Food and Drug Administrationprevents interstate shipment of or use in animal feeds of grainscontaining more than 20 parts per billion (ppb) of aflatoxin B₁. Thus,if grain containing more than 20 ppb of aflatoxin B₁ could be detoxifiedto contain less than 20 ppb of aflatoxin B₁, then this grain could beput to productive use.

It is desireable to harvest hay with sufficient moisture to prevent leafshattering during the harvesting. This is because much of the nutrientvalue of the hay is contained in the leaves, and the harvesting of dryhay results in the destruction and loss of the leaves during theharvesting process. However, storing large quantities (on the order ofseveral tons) of high moisture hay (greater than 22% moisture by weightof the hay) normally results in heating and production of mold withintwo weeks after storage. The growth of this mold substantially reducesthe feed value of the hay and can be toxic to livestock. Thus, a methodof retarding the heating and mold formation of this type of highmoisture forage is desireable.

Lactic acid production is generally accepted as an accurate measure ofthe success of the anaerobic fermentation process of silage. Thus, it isdesireable to increase the degree of fermentation of silage. Suchincrease is evidenced by an increased lactic acid content.

Animal feeds such as grains, hays, and silages have been exposed toanhydrous gaseous ammonia for the purposes of controlling microbialgrowth and spoilage, detoxifying aflatoxins, and increasing fermentationin silages. Regarding the effect of gaseous anhydrous ammonia (NH₃) ondry and high moisture (HM) coastal Bermudagrass hay, see Cross et al.,"Effect of Moisture Level and Injection of Ammonia on Nutrient Qualityand Preservation of Coastal Bermudagrass Hay," Journal of AnimalScience. Volume 61, No. 6, pages 1370-1377 (1985); and Cross et al.,"Effect of Ammonia Level and Time of Exposure to Ammonia on Nutritionaland Preservatory Characteristics of Dry and High-Moisture CoastalBermudagrass Hay," Animal Feed Science and Technology, Elsevier SciencePublishers B. V., Amsterdam, Volume 14, pages 55-65 (1986). It has beenknown prior to the invention that the exposure to gaseous ammonia can beeffected within a substantially gas tight enclosure, such as a silo or aplastic sheeting. However, gaseous ammonia is both costly and dangerousto the farmers who must store and use it.

U.S. Pat. No. 4,426,396 to Young discloses a method for treating animalfeed stuffs destined for storage. The Young method employs a solution ofurea, ammonia, and urea polymers such as biuret, triuret, cyanuric acid,and urea cyanurate to effect a chemical release of gaseous ammonia overtime. It is believed that the urease enzyme causes the urea polymers todecompose slowly. This gradual decomposition caused by the urease enzymesustains the presence of ammonia for a period of time beyond thedecomposition of the initially present urea. However, the urease enzymeis costly, and the rate at which ammonia is released cannot be reliablypredicted.

OBJECTS AND SUMMARY OF THE INVENTION

One of the principal objects of the present invention is to provide amethod and apparatus for increasing the fermentation of silage.

Another principal object of the present invention is to provide a methodand apparatus for detoxifying grain to acceptable levels of aflatoxin B₁content to enable the grain to be shipped interstate or reduce the levelenough to be safely used in animal feed.

Still another principal object of the present invention is to provide animproved method and apparatus that inhibits the formation of mold inhigh moisture forage.

A further principal object of the present invention is to provide amethod and apparatus for treating high moisture forage that results inaccelerated weight gain of the animals eating the forage.

Yet another principal object of the present invention is to provide amethod and apparatus for controlling the release of ammonia from a dryammonia precursor that is advantageous for treating animal feeds such asgrains, hays, and silages to prevent microbial growth and spoilage ofsame, for detoxification of aflatoxins in same and for improvingfermentation of silages by increasing the lactic acid content of thesesilages.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and attained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

To achieve the objects and in accordance with the purpose of theinvention, as embodied and broadly described herein, the method fortreating organic farm material such as hays, grains, and silagescomprises the following steps. The organic farm material is confined toa predetermined enclosure. A solid chemical mixture is introduced intothe enclosure. Heat is then applied to the solid chemical mixture tothereby release sufficient gaseous ammonia to the organic farm materialto prevent spoilage, reduce toxin levels, and improve fermentation ofthe organic farm material.

Preferably, the predetermined enclosure is rendered substantially gastight. For example, organic farm materials such as bales of hay can becovered with plastic sheeting which is anchored at the edges by weightssuch as mounding dirt thereon. In another embodiment, the organic farmmaterial can be enclosed in a substantially gas-tight silo. In stillanother alternative embodiment, the organic farm material can be storedin a pit dug into the ground. The organic farm material near the openingof the pit is allowed to rot to cover the top of the organic materialwith viscous decaying matter that forms a substantially gas-tight coverfor the underlying and non-decayed organic material. In still a furtheralternative embodiment, the organic material can be confined in a pitdug into the ground and covered with plastic sheeting anchored at theedges by weights such as mounting dirt thereon.

Preferably, the solid chemical mixture includes ammonium carbamate. Inaddition to ammonium carbamate, the solid chemical mixture can includeammonium hydroxide, urea, and water. A solid chemical mixture including57% ammonium carbamate, 14% ammonium hydroxide 12% urea, and 17% water,all percentages by weight, is suitable for practicing the presentinvention.

In further accordance with the apparatus of the present invention, thesolid chemical mixture is contained in a corrosion resistant container,such as a 55 gallon drum for example, and heating is provided by anelectrical resistance device disposed in the bottom of the drum orunderneath same. In a preferred embodiment of the present invention, athermostatic temperature control is provided to regulate the electricalresistance heating device. A plurality of holes are provided through thetop of the drum. The temperature control facilitates release of theammonia to the organic farm material at a controlled release rate, whichis a function of the duration of activation of the electrical resistancedevice and the temperature generated by the electrical resistancedevice.

In an alternative embodiment of the present invention, the predeterminedenclosure for confining the organic farm material can include a silo. Inanother alternative embodiment of the present invention, thepredetermined enclosure for confining the organic farm material caninclude a pit dug into the ground. In each of these latter twoembodiments of the present invention, the solid chemical mixture can beintroduced into the predetermined enclosure by sprinkling or dusting thesolid chemical mixture onto the organic farm material as it is harvestedin the field. Another way of introducing the solid chemical mixture intothe silo is to meter granular chunks of it as the organic material isblown up into the silo. This involves blowing the dry solid chemicalmixture into the silo along with the organic material.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate at least one preferred embodimentof the invention and, together with the description, serve to explainthe principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic perspective view of apparatus forpracticing the present invention; and

FIG. 2 illustrates a graphical presentation of the average percentweight loss of ammonium carbamate as a function of time at differenttemperatures.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings.

In accordance with the present invention, the method for treatingorganic farm material such as hays, grains, and silages comprises thefollowing steps. The organic farm material is confined to apredetermined enclosure. As embodied herein and shown for example inFIG. 1, organic farm materials such as bales 10 of hay can be coveredwith plastic sheeting 12. For example, the edges of the plastic sheetingcovering the bales can be anchored by weights such as mounded dirt 14thereon.

In an alternative embodiment of the present invention, the predeterminedenclosure for confining the organic farm material can include a silo. Inanother alternative embodiment of the present invention, thepredetermined enclosure for confining the organic farm material caninclude a pit dug into the ground.

Preferably, the predetermined enclosure is rendered substantially gastight. In alternative embodiments, the organic material confined to thepit can be covered with plastic sheeting weighted at the edges with dirtmounded thereon, or the organic material near the top of the pit can bepermitted to decay and form a substantially gas-tight viscous film onthe top.

In accordance with the present invention, a solid chemical mixture isintroduced into the enclosure. Preferably, the solid chemical mixtureincludes ammonium carbamate. In its pure form, ammonium carbamate isvery expensive and very unstable. A source of ammonium carbamateharvested from a urea reactor was found to be relatively inexpensive andmore stable than pure ammonium carbamate. The admixture constituting theUrea Reactor Product (URP) contained 57% ammonium carbamate, 14%ammonium hydroxide, 12% urea and 17% water (all percentages by weight).This URP admixture was supplied by Columbia Nitrogen of Augusta, Ga.,and is the URP used in the Examples discussed hereinafter.

Thus, in addition to ammonium carbamate, the solid chemical mixturepreferably includes ammonium hydroxide, urea, and water. A solidchemical mixture, including 57% ammonium carbamate, 14% ammoniumhydroxide, 12% urea, and 17% water, all percentages by weight, issuitable for practicing the present invention.

In accordance with the apparatus of the present invention, the solidchemical mixture is contained in a corrosion resistant container, suchas a 55 gallon stainless steel drum 16 shown for example in FIG. 1. Whenthe solid mixture is handled, it begins to turn partly to a liquid. Thecontainer should be airtight for shipping, but should be designed toallow for vapor release when in use. The drum has a plurality of holes22 defined through the top thereof.

In each of the silo and pit embodiments of the present invention, thesolid chemical mixture can be introduced into the predeterminedenclosure by metering aggregates of the solid mixture into the organicfarm material as the organic farm material is harvested in the field.Another way of introducing the solid chemical mixture into the silo isto meter aggregates of it as the organic material is blown up into thesilo. This involves blowing the dry solid chemical mixture into the siloalong with the organic material.

In further accordance with the method of the present invention, heat isthen applied to the solid chemical mixture to thereby release sufficientgaseous ammonia to the organic farm material to prevent spoilage, reducetoxin levels, and improve fermentation of the organic farm material.

In still further accordance with the method of the present invention, atime release method is provided for controlling the release rate of thevapors, and the time release mechanism is temperature regulated. Thepreferred temperature range is from 21° C. up to 60° C. The desiredrelease rates are obtained by utilizing temperatures intermediate tothese extremes. As shown in FIG. 2 for example, the higher release ratesare obtained at the higher temperatures, and lower release rates at thelower temperatures.

Numerous approaches in design may be taken to accomplish the objectiveof controlled vapor release. In silage for example, temperature offermentation will cause a slow release of ammonia without supplementalheat. If storage duration is indefinite, an excess of this chemicalmixture can be placed in storage bins, silos or hay stacks, and ammoniareleased as required. However if a controlled, rapid release is desired,a supplemental heating device will be required. A thermostaticallycontrolled heating device, preferably an electrical resistance device,should either be incorporated into the design of the container or theheating device designed to be added to the container. Thus, the releaseof the vapors and the amount of ammonia to be applied to the organicmaterial will be controlled by the temperature setting on the thermostatand the volume of the chemical mixture placed in contact with theorganic material.

As embodied herein and shown in FIG. 1 for example, heating ispreferably provided by an electrical resistance device 18 disposed inthe bottom of the drum or underneath same. In a preferred embodiment ofthe present invention, a thermostatic temperature control 20 is providedto regulate the electrical resistance heating device. This facilitatesrelease of the ammonia to the organic farm material at a controlledrelease rate, which is a function of the duration of activation of theelectrical resistance device and the temperature generated by theelectrical resistance device.

As shown in FIG. 2, the average percent weight loss of a solid chemicalmixture comprising 57% ammonium carbamate, 14% ammonium hydroxide, 12%urea, and 17% water, all percentages by weight, is representedgraphically as a function of time at different temperatures, including21° C., 36° C., 47° C., 57° C., 68° C., and 78° C. The numerical valuesof the plotted points are presented below in TABLE I, wherein each valueis the mean of four observations.

                  TABLE I                                                         ______________________________________                                        NUMERICAL VALUES OF PLOTTED POINTS                                                   Average Percent Weight Loss of Admixture                                      Temperatures (°C.)*                                             Time (h) 21     36       47   57     68   78                                  ______________________________________                                        0.50     13.11  17.62    38.28                                                                              42.93  77.99                                                                              80.90                               1.00     22.90  40.07    62.22                                                                              68.72  84.67                                                                              85.65                               2.00     35.35  51.88    75.08                                                                              84.06  84.80                                                                              85.80                               4.00     47.46  60.26    85.04                                                                              85.57  84.91                                                                              85.89                               6.00     52.48  66.74    85.63                                                                              85.58  85.02                                                                              86.04                               8.00     54.09  73.76    85.67                                                                              85.60  85.02                                                                              86.07                               ______________________________________                                         *Each value is the mean of four observations.                            

As embodied herein and shown for example in FIG. 1, two 55-gallon steeldrums are disposed in a hay stack. A plurality of holes 22 are formedthrough the top of each drum. An electrical resistance heater 18 isdisposed underneath each drum. The heaters are connected to a thermostatto control the temperature of the solid chemical mixture 24 andtherefore to control the release rate of the ammonia. The hay stack iscovered with plastic sheeting to prevent loss of the ammonia vapors 26which permeate and diffuse throughout the haystack.

Heating a URP admixture comprising 57% ammonium carbamate, 14% ammoniumhydroxide, 12% urea and 17% water (all percentages by weight), in thepresence of the animal feed, provided for a controlled release ofammonia which is advantageous for preventing heating and molding ingrains and hays and to improve fermentation in silages.

This invention is useful for treating feed-grains and hays to preventmicrobial growth and spoilage and for detoxification of aflatoxins ingrains. Also, this invention is useful for improving the fermentation ofsilages by increasing the lactic acid content in silages. Control ofmicrobial growth, detoxification of aflatoxins and increasedfermentation in silages is due to release of ammonia vapors.

The ammonia treatment can be considered temporary, unless storage of thefeed products is in a gas tight enclosure. Animal feeds usually are notstored in gas tight structures, therefore loss of ammonia vapors occurs.The temperature controlled, time release mechanism of the presentinvention allows for periodic release of ammonia vapors as required bythe specific situation.

Further description of the invention is provided by means of theexamples which follow.

EXAMPLE 1

The urea reactor product (URP) was applied to corn silage to determineits effect on silage fermentation. Lactic acid production is generallyaccepted as an accurate measure of the success of this anaerobicfermentation process. URP was applied at 1.5% of the weight of thesilage. The silage was placed in sealed glass containers with added URPand maintained at 60° C. for 4 hours. It then was allowed to cool backto room temperature at its own rate. After 12 hours at room temperature,it then was heated to 55° C. and maintained at 55° C. for 2 hours.Subsequently, the containers were maintained at room temperature forfour weeks, and aliquot samples removed and frozen for later analysisfor lactic acid content. The increased lactic acid content with URPaddition is shown in TABLE II. This demonstrates the advantage of thisURP admixture product for increasing fermentation and therefore thepreservation and feeding value of the silage. Also, the additionalnitrogen added to the silage from the URP can be utilized by rumenmicroorganisms of cattle to synthesize usable protein.

                  TABLE II                                                        ______________________________________                                        EFFECT OF UREA REACTOR PRODUCT (URP)                                          ON LACTIC ACID CONTENT OF CORN SILAGE                                                         % lactic acid.sup.a                                           ______________________________________                                        Control (no additive)                                                                           1.94                                                        URP.sup.b,c       2.52                                                        ______________________________________                                         .sup.a Each value is the mean of two samples.                                 .sup.b URP was applied at 1.5% of the weight of the silage.                   .sup.c Media was initially exposed to 60° C. for 4 hours and           55° C. for 2 hours, 12 hours later.                               

EXAMPLE 2

URP was added to aflatoxin contaminated whole corn grain at 6% of theweight of the corn. The corn grain was either dry (8.5% moisture byweight) or water was added to increase the moisture content to 20%moisture (by weight). Samples were stored in airtight glass containers,and the temperature was raised to 60° C. The temperature was maintainedat 60° C. for 2 hours and then allowed to return to room temperature.After a 48 hour interval at room temperature, the process was repeatedthree more times so that a total of 8 hours was spent at a temperatureof 60° C. The samples were then stored at room temperature for threeweeks, ground and frozen until analysis for aflatoxin B₁ content. Asshown in TABLE III, aflatoxin B₁ content was reduced to 35 ppb with drycorn and to less than 5 ppb (limit of detectability of procedure) for20% moisture corn.

Aflatoxin is a mycotoxin produced by the mold aspergillus flavus and isvery toxic to all animal species. The invention would be useful forpreventing mold growth in grains in long-term storage programs byperiodically releasing ammonia vapors. Also, if mold growth has occurredand aflatoxins are produced, detoxification would be possible. Currentlythe U.S. Food and Drug Administration does not allow grains containingmore than 20 ppb to be shipped interstate or used in animal feeds.Therefore, this invention would be useful to recover the use of much ofthis grain.

                  TABLE III                                                       ______________________________________                                        EFFECT OF UREA REACTOR PRODUCT (URP) ON                                       AFLATOXIN B.sub.1, CONTENT OF WHOLE SHELLED CORN                                             Aflatoxin B.sub.1, ppm                                         Item             Dry corn       20 moisture corn                              ______________________________________                                        Control.sup.b  (no additive)                                                                   375 ppb        375 ppb                                       URP.sup.b,c      35 ppb         less than 5 ppb                               ______________________________________                                         .sup.a Each value is the mean of two samples.                                 .sup.b Temperature regime was 60° C. for 2 hours at 48 hour            intervals and 4 intervals.                                                    .sup.c URP was applied at 6% of the weight of the corn.                  

EXAMPLE 3

The effectiveness of ammonium carbamate as the source of ammonia for thetreatment of high moisture coastal bermudagrass forage was demonstratedthrough an ammoniation study and a metabolism study.

Approximately five tons of high moisture bermudagrass hay (29% moistureby weight) was harvested in square bales and covered with plastic, suchas shown in FIG. 1. URP (9.9% of the weight of the hay) was placed in 55gallon drums with an electrical resistance heater coil under the drum.The temperature of the URP media was maintained at 60° C. for 7 days.Normally this type of high moisture forage would heat and mold within 2weeks after storage. Approximately 30 days after ammoniation, theplastic cover was removed and the hay bales moved to a covered shed forstorage until feeding. There were no visible signs of molding or heatdamage to the hay.

Twelve yearling beef heifers (averaging 281 kg weight, initially) wereplaced on either dry control hay (15% moisture) or URP treated hay.Additionally, all heifers received 1% of their body weight as corn graindaily. As shown in TABLE IV, Heifers receiving the URP hay gained weightat a faster rate and tended to be more efficient in converting feed toweight gain.

                  TABLE IV                                                        ______________________________________                                        EFFECT OF UREA REACTOR PRODUCT (URP)                                          TREATMENT OF BERMUDAGRASS HAY ON                                              PERFORMANCE OF BEEF HEIFERS                                                                 Treatment.sup.a                                                                 Untreated URP Treated.sup.b                                   Item            Hay       Hay                                                 ______________________________________                                        Initial wt, kg  281.5     279.9                                               Final wt, kg    349.7     361.0                                               Total gain, kg  68.2      81.1                                                Average daily gain, kg                                                                        .81       .97                                                 Feed/gain, kg   6.0       5.4                                                 ______________________________________                                         .sup.a Each value is the mean of six animals.                                 .sup.b Hay was enclosed in polyethylene and treated with URP. URP was         placed in steel drums and electrical resistance heat added (60° C.     for 7 days).                                                             

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the method of the presentinvention without departing from the scope or spirit of the invention.Thus, it is intended that the present invention covered themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. A method for treating organic farm materialincluding one or more of hays, grains and silages, the method comprisingthe steps of:(a) confining the organic farm material to a predeterminedenclosure; (b) introducing a solid chemical mixture into said enclosure;(c) heating said solid chemical mixture to thereby release sufficientgaseous ammonia to said organic far material to accomplish at least oneof the following: prevent spoilage, reduce toxin levels, and improvefermentation of said organic farm material; and wherein: said solidchemical mixture includes ammonium carbamate, ammonium hydroxide, urea,and water.
 2. The method defined in claim 1, further including the stepof:rendering the predetermined enclosure substantially gas-tight.
 3. Themethod defined in claim 2, wherein:the step of confining the organicmaterial to a predetermined enclosure includes covering the organicmaterial with plastic and weighting the edges of the plastic to preventgas from leaking from around the edges of the plastic.
 4. The methoddefined in claim 1, wherein:said solid chemical mixture includes inweight percentages, 57% ammonium carbamate, 14% ammonium hydroxide, 12%urea, and 17% water.
 5. The method defined in claim 1, wherein:the stepof introducing the solid chemical mixture into the enclosure includessprinkling discrete particles of the mixture onto the organic farmmaterial as the organic farm material is being harvested in the field.6. The method defined in claim 1, wherein:the step of confining theorganic farm material to a predetermined enclosure includes blowing theorganic farm material up into a silo.
 7. The method defined 6,whereinthe step of introducing the solid chemical mixture into theenclosure includes blowing discrete particles of the chemical mixture upinto the silo as the organic farm material is blown up into, the silo.8. The method defined in claim 1 wherein:the step of confining theorganic farm material to a predetermined enclosure includes placing theorganic farm material into a pit dug into the ground and covering thepit with plastic which is weighted around the edges to substantiallyprevent leakage of gas from around the edges of the plastic.
 9. Themethod defined in claim 1, wherein:the step of confining the organicmaterial to a predetermined enclosure includes the step of placing theorganic material into a pit dug into the ground and letting the organicmaterial at the top of the pit rot to seal itself.
 10. The methoddefined in claim 1, wherein:said heating step is carried out using athermostatically controllable electrical resistance device.
 11. Themethod defined in claim 10, wherein:said ammonia is released to saidorganic farm material at a controlled release rate, said release ratebeing a function of the duration of activation of said electricalresistance device and the temperature of said electrical resistancedevice.
 12. The method defined in claim 1, whereby: corn silagefermentation is enhanced.
 13. The method defined in claim 1, whereby:aflatoxin levels in corn grain are reduced.
 14. The method defined inclaim 1, whereby:heat damage and molding of high moisture forage areprevented.
 15. A method for treating one or more of the group includingharvested crops, animal feeds, feedgrains grains, and silages, themethod comprising:providing a solid chemical composition containingammonium carbamate, ammonium hydroxide, urea, and water in the midst ofthe crops and feeds to be treated; raising the temperature of said solidchemical composition to release gaseous ammonia; controlling thetemperature of said solid chemical composition to release sufficientgaseous ammonia to said crop or feed to accomplish at least one of thefollowing: prevent spoilage, reduce toxin levels, and improvefermentation of said crop or feed.